The field of the invention pertains to devices for viewing a television screen and, in particular, for enhancing the depth perception of the viewer.
Enhanced depth perception of television scenes or "three-dimensional television" in a convenient and inexpensive form has been a long-sought goal. The approaches to enhanced depth perception have generally required a "stereo" or dual broadcast signal supplied to the television for simultaneous or alternating imaging on the screen. Separation of the stereo images has been accomplished by either relatively simple means, such as glasses with polaroid or colored lenses, or by more sophisticated means, such as liquid crystal glasses connected by wire, infrared or radio signal to the television. Viewing systems, based on the above devices, have had limited success at best in specialized applications. To date, no system or device has met with acceptance by the general public for commercial television broadcasts to the home-viewing audience.
Other systems have been proposed, such as the device disclosed in published UK patent application GB2160053A. This device consists of a pair of parallel grids, each comprising vertical bars with gaps between the bars. The vertical bars separate the right and left images shown on the television screen into images that can only be seen by the right or left eye. The device, however, requires the broadcast signal be specially processed into vertical narrow alternate strips.
A second similar device is disclosed in Italian patent 694923 wherein parallel grids comprise both vertical polarizing grids and horizontal polarizing grids mounted in a frame fastened over the television screen. The viewer wears polarizing glasses to provide the stereoscopic separation. This device requires a stereo broadcast to the television receiver and system coordination between the broadcast signal and the polarizing grids.
To avoid the expensive crystal or polarizing units or color filter glasses and laser, holographic or stereo broadcast signals required by the above approaches to enhanced depth or three dimensional television the following criteria should be met for a television optical viewing device:
(a) portable, compact, light-weight, self-contained; PA1 (b) uses no electricity or other energy source; PA1 (c) has no moving parts; PA1 (d) simple and basic, both in design and concept; PA1 (e) can be used with virtually any television receiver, whether color or black and white; PA1 (f) no optical or other hazards to the users; PA1 (g) enables the user to experience the increased pleasure; wonder and realism of the three dimensional effect or illusion while viewing television broadcasts, cablevision, videocassettes and laser discs.